function lazyload(){
    $('img').each((i,item)=>{
        let top = $(item).offset().top
        let sTop = $(window).height()  + $(document).scrollTop()
        if(top <= sTop){
            let src  = $(item).attr('data-original')
            $(item).attr('src',src)
        }
    })
}
let t 
$(window).scroll(function(){
    if(t) return 
    t = setTimeout(()=>{
        lazyload()
        t = null
    },1000)
    
})